1. Field of the Invention
The invention relates to a nuclear reactor fuel assembly with fuel rods which contain nuclear fuel, the fuel rods being guided in feedthroughs formed in a head plate, and at least part of the fuel rods being fastened in the feedthroughs, a fuel assembly box in which the fuel rods are disposed, the box having a cross piece located inside an upper corner with which it rests on a corner bolt located on the upper surface of the head plate, the box and an angular part being bolted to the corner bolt with a screw bolt, the angular part being fitted to the fuel assembly box on the outside of two sides of the fuel assembly box and the angular part having leaf springs extending in the longitudinal direction on each of the two sides of the box, the screw bolt having an expansion shank with a reduced diameter, the screw bolt being captively associated with the angular part by means of a screw head on the top of the angular part, and a mounting body.
2. Description of the Related Art
Such a nuclear reactor fuel assembly is known from German Published, Non-Prosecuted Application DE-OS No. 28 2.4 265, corresponding to U.S. Pat. No. 4,304,635. The mounting body in that device is located on the underside of the angular part of this prior art nuclear reactor fuel assembly and is a cylindrical pin disposed in a transverse hole formed in a threaded bolt which is secured against falling out of the transverse hole by a welded spot on the threaded bolt.
The cross section of the threaded bolt is reduced at the location of the transverse hole. Furthermore, the material of which the threaded bolt is made is sensitized at that location by a welded spot. Therefore, it is possible for the threaded bolt to break not at the expansion shank which has a reduced diameter and which is provided for this purpose, but rather at the transverse hole. This can occur, for instance, if expansion forces act on the threaded bolt in the longitudinal direction, while inserting the nuclear reactor fuel assembly into a boiling-water nuclear reactor.
It is accordingly an object of the invention to provide a nuclear reactor fuel assembly which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, and to ensure that the threaded bolt always breaks at the expansion shank which has a reduced diameter and which is provided for this purpose, if the expansion forces are excessive, and that it breaks nowhere else.